Today's machines, and particularly large off-highway work vehicles, are becoming increasingly complex in their design thus making it more and more difficult for service personnel to locate defects in machine sensors and systems. This is particularly true of intermittent defects not resulting in a breakdown of a system or the vehicle but which interfere with its operation.
A major frustration when troubleshooting electrical problems on a large work vehicle are the intermittent problems. Typically, the operator reports some symptom to a technician and before the technician can get to the machine the problem is no longer present.
If the condition is not present it is helpful for the technician to re-create the fault condition. In many cases the fault condition is caused by a short to ground potential or an open circuit. To recreate these fault conditions, the technician manipulates the wire harnesses or wire connectors to determine the point at which the fault has occurred.
Prior art systems have indicated when fault conditions are present. In connection with such systems, the technician must view a visual display to determine whether the condition is present. In troubleshooting intermittent problems when the fault condition is not currently present, the technician must manipulate wire harnesses and connectors to recreate the fault and thus cause the fault indication to be displayed. When the fault condition is present, the technician must manipulate wire harnesses and connectors and observe whether the manipulations eliminate the fault and thus cause the fault indication to disappear.
In many cases, however, the machine is of sufficient size that the technician must leave the area of the diagnostic tool to recreate the fault condition. Therefore, any visual indicator provided by the diagnostic tool is not visible to the technician. To effectively troubleshoot the electrical system on such a large machine, typically two or more technicians are required and repair expenses are thus greatly increased. Similarly, the vehicle may not be repairable immediately if only a single technician is available.
In addition, these machines typically include switch-type sensors that are either in an open voltage or grounded condition. One of the voltage conditions is defined as a fault condition. In most cases, the fault condition is defined as the open voltage condition thus whenever the wire between the sensor and the display is severed or disconnected, a fault condition is indicated. Similarly, when the parameter being sensed by the switch-type sensor is at a warning level to actuate the sensor, the switch-type sensor disconnects the sensor output from ground potential.
Some prior art systems have illuminated a warning light for each switch-type sensor that is in a fault condition. Each warning light is associated with one of the switch-type sensors and is illuminated when the display input associated with that switch-type sensor is indicating a fault condition. While adequate for many purposes, in other cases it is advantageous to also indicate the pin number of the input associated with the switch-type sensor. Optimally, the technician should be able to determine the pin number of each of the warning lights indicating a fault condition even though there are more than one of such warning lights. This would allow technicians to more readily identify the fault condition and associate the sensor having the fault condition to the relevant connector pin.
The present invention is directed at overcoming one or more of the problems as set forth above.